I have recently begun Hab-It. I have done it two days now and today I have some lower back pain if I lean too far back (I have a baby and a toddler, so lots of child lifting). I think it’s my multifidi. Does this mean I am doing the bum-lift type movement wrong?

Romi,
More than likely it means that you are working muscles that you haven’t before or in a long time. It is good for us to move our joints through a full range of motion – into full extension and full flexion, but if we haven’t done this in a while becuase we hold the same posture most of our days, then we will feel soreness. Just take it easy as you roll through your motion and stop short of any sharp pain as your body adjusts.